DESCRIPTION: The goals of this proposal are to develop improved methods to prepare and purify large amounts of oligodeoxyribonucleotides containing chemically well-defined damage at unique and specific locations, to use these molecules to determine how specific adducts affect the three-dimensional structure of a DNA duplex, and to attempt to relate these structural changes to the mutations and biochemical effects that they induce. The data generated in these studies will be used to test the hypothesis that the type of mutation and other biochemical effects induced by DNA adducts are dependent on the adduct structure and the DNA sequence within which it is located. Retrospective analysis of these biological consequences are expected to provide an understanding of the molecular mechanism of mutagenesis. To reach these goals, Dr. Romano plans to use primarily multidimensional NMR, but also circular dichroism and chemical methods, to elucidate the three-dimensional structure of DNA modified with acetylaminofluorene (AAF), aminofluorene (AF), and benzo(a)pyrene (BaP) adducts. These DNA adducts represent relevant and well-studied examples of chemical carcinogens. He also plans to use physical and enzymatic techniques to characterize the interactions between a DNA polymerase and/or a DNA helicase and DNA containing these DNA adducts.